Asymmetric Organocatalytic Sequential Reaction of Structurally Complex Cyclic Hemiacetals and Functionalized Nitro-olefins To Synthesize Diverse Heterocycles
作者:Jun-Ping Pei、Ying-Han Chen、Yan-Kai Liu
DOI:10.1021/acs.orglett.8b01386
日期:2018.6.15
Structurally complex cyclic hemiacetals bearing a racemic tetrasubstituted stereocenter have been prepared in a concise manner and were successfully used in an organocatalytic enantioselective sequence to react with functionalized nitro-olefins, providing bicyclic acetal-containing compounds as two separable epimers with excellent stereoselectivity. The reaction showed broad substrate scope, with respect
Phosphine-Catalyzed Chemoselective Reduction/Elimination/Wittig Sequence for Synthesis of Functionalized 3-Alkenyl Benzofurans
作者:Yan-Cheng Liou、Heng-Wei Wang、Athukuri Edukondalu、Wenwei Lin
DOI:10.1021/acs.orglett.1c00737
日期:2021.4.16
An efficient protocol for the construction of functionalized 3-alkenyl benzofurans is demonstrated under metal-free conditions using catalytic amount of phosphine proceeding an intramolecular Wittigreaction. This one-potreaction initiated by the phospha-Michael addition of phosphine to O-acylated nitrostyrene, in which phosphine was in-situ-generated from the chemoselective reduction of phosphine
Enantioselective conjugate additions of in situ generated 2-alkoxycarbonyl-3(2H)-furanones to three distinct types of π-electrophiles (terminal alkynones, α-bromo enones, and α-benzyl nitroalkenes) are reported. Catalysis by a nickel(II)–diamine complex provided alkynone-derived adducts with high enantioselectivity, preferentially as the Z-isomers, and completely suppressed the undesired O-alkylation